Wiring Diagram Needed 1994

[Duvall]

The climate controls in my truck have only 3 speeds for the blower motor. From what I have read this changed in the later 1993 models and 1994 to a 4 speed.

I have yet to find the complete blower wiring harness to change it to the 4 speed.

If someone has the wiring diagram for a 1994 truck they can post up I will add the relay, resistors and wiring myself. I believe the control unit is the same and will run the 4 speeds, at least that is what I have been reading.

 

[MrMarty51]

The climate controls in my truck have only 3 speeds for the blower motor. From what I have read this changed in the later 1993 models and 1994 to a 4 speed.

I have yet to find the complete blower wiring harness to change it to the 4 speed.

If someone has the wiring diagram for a 1994 truck they can post up I will add the relay, resistors and wiring myself. I believe the control unit is the same and will run the 4 speeds, at least that is what I have been reading.

I’ll see what the Chiltons book has.

 

[MrMarty51]

 

[Duvall]

Thank you!

 

[MrMarty51]

Does that fit ?

 

[Jaryd]

These are from a 94 factory service manual. I only see 3 speeds on it though

 

[Duvall]

@Jaryd , Thank you.

I was hoping someone had the factory manual.

I just need to look at these and figure the four speeds from three relays.

 

[MrMarty51]

@Jaryd , Thank you.

I was hoping someone had the factory manual.

I just need to look at these and figure the four speeds from three relays.

The highest speed has no relay involved, direct battery voltage. I do think it might flow through from a relay though.

 

[MrMarty51]

Yeah, the three lower speeds are run through resistors, the high speed fan is run through a relay and is full battery voltage. It is the switch itself that has the four positions, three positions are through the resistors and the fourth is through the relay.
The top wiring schematic from the Chiltons manual shows it.

 

[THEFERMANATOR]

The factory diagrams can be found here.

GMT400 CK Manual Project - The 1947 - Present Chevrolet & GMC Truck Message Board Network

GMT400 CK Manual Project The 1988 - 1998 GMT400 Chevy & GMC Pickups Message Board

67-72chevytrucks.com

 

[Duvall]

Yeah, the three lower speeds are run through resistors, the high speed fan is run through a relay and is full battery voltage. It is the switch itself that has the four positions, three positions are through the resistors and the fourth is through the relay.
The top wiring schematic from the Chiltons manual shows it.

All 4 speeds run through relays on the 1994, 3 speeds in the case of my 1993. The top drawing is from 1995-98. It appears to have different controls.

So its a matter of which relays are on the get the in between speeds. For instance, 1993 the low and high relay are on for lowest speed, for the medium speed the high relay drops out, for high speed, the high relay comes back on and the low relay drops out.

 

[Duvall]

The factory diagrams can be found here.

GMT400 CK Manual Project - The 1947 - Present Chevrolet & GMC Truck Message Board Network

GMT400 CK Manual Project The 1988 - 1998 GMT400 Chevy & GMC Pickups Message Board

67-72chevytrucks.com

Thank you.